A total of 240 Ross 308 day-old male broiler chicks within a completely randomized design were used in this experiment to evaluate the effects of dietary inclusion of turmeric powder and cinnamon powder on performance and some immune responses of broiler chickens. Dietary treatments were as follow: a corn-soybean meal basal diet (control); basal diet + 10 ppm avilamycin; basal diet + 2.5 g/Kg turmeric powder; basal diet + 7.5 g/Kg turmeric powder; basal diet + 2.5 g/Kg cinnamon powder; and basal diet + 7.5 g/Kg cinnamon powder. During the experiment, feed intake, body weight gain, and feed conversion ratio were measured in the beginning and the end of starter (0-21 d.) and grower (22-42 d.) periods. On 21 d. of age, two chicks from each replicate were randomly selected and blood samples were taken. Differential enumeration of heterophils, lymphocytes, and monocytes were done. Also, antibody titers against IBV, IBD, and NDV vaccines were measured. Addition of 2.5 g/Kg turmeric powder increased body weight gain in the starter period and improved feed conversion ratio in the starter and entire periods of the experiment, when compared to the control (P). Also, inclusion of 10 ppm avilamycin into diet improved feed conversion ratio in the grower and entire periods of the experiment, comparing to the control (P). Inclusion of turmeric powder at 2.5 g/Kg or 7.5 g/Kg and cinnamon powder at 7.5 g/Kg declined the heterophil to lymphocyte ratio (P). The results of this study showed that turmeric powder at the level of 2.5 g/Kg would be a potential alternative for antibiotic growth promoters. Also, reducing heterophil to lymphocyte ratio by turmeric and cinnamon powders, introduce them as potential stress alleviators in broiler chickens.